Hard Engineering to Increase Water Supply
- There are conflicting views over what is the best approach to managing water supplies
- Economic stakeholders prefer hard-engineered schemes, and environmental stakeholders a more natural and sustainable approach
Hard-engineered schemes
- These need capital, technology and long-term maintenance to be successful
- Schemes include:
- Water transfer schemes
- Mega dams
- Desalination plants
Water transfer schemes
- These attempt to make up for water deficits through constructing systems of canals, pipes, and dredging over long distances to transfer water from a drainage basin of surplus supplies to areas of deficit
- The Kielder reservoir in Northumberland supplies water to the cities of Newcastle-upon-Tyne, Sunderland, Durham, Darlington and Middlesbrough via a water transfer
| Source | Destination |
| Less water - reduced amounts of water for local consumption which may lead to water poverty | More water — solves existing demand and may lead to increased usage |
| Ecosystem changes - ecosystems may be degraded, destroyed, have lower functioning and productivity as a result of the decreased water supplies |
Development demands — increase supplies may increase urban, along with tourist sites such as golf courses. It will contribute to improved human health due to better sanitation |
| Pollution - increased pollution due to less opportunity for dilution, so pollutants are more concentrated |
Agricultural demands — the increased availability of water means that famers may use it unsustainably e.g. flood irrigation. Pollution from fertilisers cause eutrophication and salination of water courses, which is then transferred in the water transfer project causing ecosystem degradation elsewhere |
China’s south-north water transfer
- One of the largest water transfer projects in the world
- Planning began in 1952, with work starting in 2002, and is expected to be completed by 2050
- It aims im is to divert 45bnm³ of water a year from surplus river basins in the south and east to the north where there is frequent water deficits in places such as Beijing and Tianjin
- The project will cost US$62 billion to complete and will involve the resettlement of people which is not popular
- The 3 main diverting routes:
- Western route - started in 2010, through difficult, high-altitude terrain. As the route will pass high industrial activity, it is feared that water will become polluted on transfer, as well as reduce the volumes in the Yangtze, causing issues with sediment and the ecosystem
- Central route - this is a 1267km diversion with some of the water from the Three Gorges Dam being used in order help
- Eastern route - this route is 1,155km long diversion from the Yangtze river next to Shanghai to Beijing and Tianjin in the north
- The main stakeholders are the government sponsored ‘South to North’ Water Transfer Project Company and corporate civil engineering companies building 3 major canals, pipelines, tunnels and pumping stations
Mega dams
- Dams block rivers so that reservoirs of water build up behind, rather than drain away
- Dams provide large, reliable supplies of drinking water and reduces water insecurity, especially in areas of seasonal precipitation
- Dams and reservoirs can also prevent flooding, as the flow of the river is controlled, and can generate electricity through hydroelectric power (HEP)
- Nearly 60% of the world's major rivers have large dams of which the Aswan, Hoover and 3 Gorges are amongst the largest
- Although thought of as environmentally friendly, mega dams have issues aside of the huge economical costs of construction
- Dams alter ecosystems - downstream ecosystems rely on water and sediment, both of which are held back by big dams, making downstream land less fertile
- Dams displace people, communities and destroy cultural heritage
- Flooding of the reservoir submerges land and destroys plants and animals
- Dams reduce water quality and waste water - large surface areas of reservoirs increase rates of evapotranspiration and trap sediment and agricultural runoff, increasing rates of eutrophication and vector diseases
Desalination plants
- Extracts the salt from seawater to enable it to be used for drinking and irrigation
- Expensive, salt waste can damage marine ecosystems and the process uses large amounts of energy
- As the price of freshwater increases, some countries will look to the sea for water supplies
- Dubai has already done this, as has Kuwait and Saudi Arabia
- Alicante II Seawater plant in Spain and Tampa Bay Water plant, USA
- Although it is a sustainable process, it is considered a hard engineered process due to the inputs of technology and energy and it has an ecological impact on marine life
